In this lesson students will dive deeper into Punnett squares (Dihybrid crosses). Recalling prior knowledge about monohybrid crosses I will ask students what they think should change in the Punnett Square in order to accommodate this 2nd trait being studied (using the board to write out their answers). We will do a couple examples as a class before I give the students their own problems to work with in groups of 2. I am hoping that students will see the relationship between mono/dihybrid crosses and the ratios that they create (each type of cross has a set ratio). At the end of this class I will be giving students a rubric to go along with their MENDALIEN GENETICS Project.
Opportunities to Learn:
Depth of Knowledge
Level 1 - Represent in words or diagrams a scientific concept or relationship
Level 2 - Specify and explain the relationship between concepts
Prerequisite Knowledge
Students will need to use their prior knowledge of monohybrid crosses as well as the information they read in the HW packet to complete the "Science Starter" activity at the very beginning of the class. On the front of this worksheet there is an example of a cross between pea plants showing the P1, F1, and F2 generations and on the back their is a series of questions about the diagram. After taking 5-10 minutes, I will go over the worksheet with them, calling on random students to answer each question. This will help them recall prior information which they will be building on in todays class about Dihybrid Crosses.
Plans for Differentiating Instruction
Giving students lots of visuals and examples then letting them "do" is my plan for differentiating instruction. Walking around the room and keeping myself available for questions are other ways in which I can keep students on task and on the right track. What will you do to challenge your strongest students? What about students are are struggling?
Accommodations and modifications
In this lesson there are a few things to help differentiate instruction. The first is the science starter. For students who struggled a little bit more than others in the last class, this starter is a little more student friendly. The diagram on the front is labeled as well as large (it takes up the whole front page). The back questions aren't "easy" but they all relate to the front diagram which can be easily interpreted by the students. The second differentiation would be the dihybrid cross worksheet. Since students have been working on dihybrid crosses the entire class, those that are having difficulty with the format of it can benefit from this worksheet because it is already drawn out for them on the front.
Environmental factors
Students will be in their normal seats, 2 at a table so they can work together if need be.
Materials
Copies of Science Starter for all students
Copies of Dihybrid cross wkst for all students
Objectives:
Students will DIFFERENTIATE between monohybrid and dihybrid crosses
Students will make CONNECTIONS between the differences in ratios
Students will DETERMINE ratios for themselves given different types of crosses (homozygous/heterozygous)
Will they be able to explain the difference between the two types of crosses?
Instruction:
Opening:
Self Directed Question: (More of a statement) "This Science Starter that I have for you asks you to look at the diagram of a monohybrid cross on the front of the sheet and answer questions about it on the back, using the information talked about in last class, show me what you learned."
Sharing: After giving students about 10 minutes to do this worksheet, I will go over it with them (having my own copy on the overhead and writing down their answers as I call on each student at random. When each student answers I will put the answer to the class to see if anyone disagrees, "Does everyone agree with this answer?"
This isn't a big deal, but you're using too many words. How about:
Examine the diagram on the worksheet and answer the questions on the back.
This is a bigger deal. Look at your transition statement and ask yourself:
Why should they care??? How you tied the idea of dihybrid crosses to THEIR lives or their world? If not, then you need think of another statement. Do they have a need to know?
Segue statement: "Now that we've recalled a little bit about what we learned last class, MONOHYBRID crosses, lets take a look at something a little more in depth, DIHYBRID crosses!"
Topic: Dihybrid Crosses are a little more complicated then monohybrid crosses. They involve 2 traits and make a larger 4x4 punnett square rather than a 2x2 in monohybrid crosses. These punnett squares also generate different ratios 9:3:3:1 when crossing two heterozygous parents (monohybrid crosses are 3:1). Each type of cross provides a different ratio of phenotypes and genotypes and it is up to my students to explore the different types of crosses to see what they get.
You use a lot of new words in this statement. How/when will you define them?
The GOAL for this class just like the last will be written up on the board for students to see: By the end of this class, I would like all students to be able to create their own Dihybrid cross, and then organize the genotypes and phenotypes into ratios.
This is a very technical goal. Couldn't student just follow your example and do this successfully? How will you know that they understand what they are doing?
I will start by drawing a normal 4 boxed punnett square on the board
"Remember this guys? Its a normal, monohybrid cross punnett square. Mendel used this to study ONE trait at a time. However, Mendel decided to get a little more complicated with his work. He introduced a SECOND trait into the cross and studied 2 at the same time, can you guys manipulate this punnett square and find a way to accommodate that second trait? Work it out on a piece of paper and discuss with your partner."
Did Mendel choose to complicate his work for a reason? What there data that the more simple explanation did not address?
Students will not know what it means to "study a second trait." You need to provide a question or challenging example and then have them discuss in pairs possible answers. What justification, in addition to their "guess," will you want them to share out?
I will open this up for discussion and students will talk to their partner at their table to generate ideas about how they could manipulate a punnett square to accommodate another trait being studied. After discussing what some of the groups come up with (possibly one group coming up with a correct answer) I will show them how Mendel introduced this second trait. NIce! I like the idea of allowing students to try to answer question before you share Mendel's approach.
"If you guys look in your books at page 261 you will see the same thing you saw in Monohybrid crosses, a punnett square. However, obviously its a little different. Can anyone tell me why this punnett square is different?"
"You guys." Really? Are you a teacher or a classmate? An easy thing you can do to elicit respect is to act/speak like an adult. It's your choice, but this is a simple step. The young women in your classes could take offense.
Size (# of squares)
2 traits instead of 1
Different RATIO
Do students learn why these ratios appear, or is this a rote rule? Can you explain it to them?
Hopefully students will name all 3 of these, if not I am assuming that the one they will not get is the difference in ratios between the monohybrid and dihybrid cross. Obviously I will not just give them the answer, but will help guide them to it.
"You guys got the first 2 right off the bat, but there's another one that is a little harder to get. Look at the different phenotypes, how does the amount of different phenotypes in this cross compare to that of the monohybrid cross?"
Activity 2: Dihybrid Cross worksheet
After having students read a little bit about Dihybrid crosses I will hand them a worksheet which will engage them further. What will you have them read? Do you remember reading in class? Why didn't you assign this the previous night?
Master 16 Dihybrid Worksheet
Students will work on this worksheet independently and then after a little while we will come together as a class and go over it.
Can you think of a way not to go over the worksheet? This is usually a waste of time, since no one pays attention. (Why should they?)
Activity 3: MendALIEN Genetics
Now that students have the concept of Mendel and all of his work, I am going to introduce my project for this section which is titled MendALIEN genetics. This is a project that is due on the same day as the Chapter Test (Day 5) and gives students the chance to create their own alien by using punnett squares (see rubric, procedure, questions for more details). ------ This has not yet been created, I am working on it.
Reading these aloud with the class will guarantee that students understand what is expected of them and how I will be grading them on this assignment as well. Any questions can be answered and students will have the opportunity to begin working on this project if they want (although I don't expect their to be much class time left by the end of the period).
What will you do to generate enthusiasm for the project?
Closure:
Going over Dihybrid Cross worksheet
Clarifying any questions about project
Open discussion about anything we have talked about
How about asking a summary question for the day and having students volunteer answers?
Lesson Plan
Lesson Title: No Punnett Intended
State Standards: GLEs/GSEs
http://riscienceteachers.wikispaces.com/LS3+(9-11)+-+7Context of Lesson:
In this lesson students will dive deeper into Punnett squares (Dihybrid crosses). Recalling prior knowledge about monohybrid crosses I will ask students what they think should change in the Punnett Square in order to accommodate this 2nd trait being studied (using the board to write out their answers). We will do a couple examples as a class before I give the students their own problems to work with in groups of 2. I am hoping that students will see the relationship between mono/dihybrid crosses and the ratios that they create (each type of cross has a set ratio). At the end of this class I will be giving students a rubric to go along with their MENDALIEN GENETICS Project.Opportunities to Learn:
Depth of Knowledge
Level 1 - Represent in words or diagrams a scientific concept or relationshipLevel 2 - Specify and explain the relationship between concepts
Prerequisite Knowledge
Students will need to use their prior knowledge of monohybrid crosses as well as the information they read in the HW packet to complete the "Science Starter" activity at the very beginning of the class. On the front of this worksheet there is an example of a cross between pea plants showing the P1, F1, and F2 generations and on the back their is a series of questions about the diagram. After taking 5-10 minutes, I will go over the worksheet with them, calling on random students to answer each question. This will help them recall prior information which they will be building on in todays class about Dihybrid Crosses.Plans for Differentiating Instruction
Giving students lots of visuals and examples then letting them "do" is my plan for differentiating instruction. Walking around the room and keeping myself available for questions are other ways in which I can keep students on task and on the right track.What will you do to challenge your strongest students? What about students are are struggling?
Accommodations and modifications
In this lesson there are a few things to help differentiate instruction. The first is the science starter. For students who struggled a little bit more than others in the last class, this starter is a little more student friendly. The diagram on the front is labeled as well as large (it takes up the whole front page). The back questions aren't "easy" but they all relate to the front diagram which can be easily interpreted by the students. The second differentiation would be the dihybrid cross worksheet. Since students have been working on dihybrid crosses the entire class, those that are having difficulty with the format of it can benefit from this worksheet because it is already drawn out for them on the front.
Environmental factors
Students will be in their normal seats, 2 at a table so they can work together if need be.Materials
Objectives:
- Students will DIFFERENTIATE between monohybrid and dihybrid crosses
- Students will make CONNECTIONS between the differences in ratios
- Students will DETERMINE ratios for themselves given different types of crosses (homozygous/heterozygous)
Will they be able to explain the difference between the two types of crosses?Instruction:
Opening:
Self Directed Question: (More of a statement) "This Science Starter that I have for you asks you to look at the diagram of a monohybrid cross on the front of the sheet and answer questions about it on the back, using the information talked about in last class, show me what you learned."This isn't a big deal, but you're using too many words. How about:
- Examine the diagram on the worksheet and answer the questions on the back.
This is a bigger deal. Look at your transition statement and ask yourself:- Why should they care??? How you tied the idea of dihybrid crosses to THEIR lives or their world? If not, then you need think of another statement. Do they have a need to know?
Segue statement: "Now that we've recalled a little bit about what we learned last class, MONOHYBRID crosses, lets take a look at something a little more in depth, DIHYBRID crosses!"Topic: Dihybrid Crosses are a little more complicated then monohybrid crosses. They involve 2 traits and make a larger 4x4 punnett square rather than a 2x2 in monohybrid crosses. These punnett squares also generate different ratios 9:3:3:1 when crossing two heterozygous parents (monohybrid crosses are 3:1). Each type of cross provides a different ratio of phenotypes and genotypes and it is up to my students to explore the different types of crosses to see what they get.
You use a lot of new words in this statement. How/when will you define them?
The GOAL for this class just like the last will be written up on the board for students to see: By the end of this class, I would like all students to be able to create their own Dihybrid cross, and then organize the genotypes and phenotypes into ratios.
This is a very technical goal. Couldn't student just follow your example and do this successfully? How will you know that they understand what they are doing?
Engagement:
I will start by drawing a normal 4 boxed punnett square on the boardActivity 1: Demonstration: Manipulating monohybrid crosses
- "Remember this guys? Its a normal, monohybrid cross punnett square. Mendel used this to study ONE trait at a time. However, Mendel decided to get a little more complicated with his work. He introduced a SECOND trait into the cross and studied 2 at the same time, can you guys manipulate this punnett square and find a way to accommodate that second trait? Work it out on a piece of paper and discuss with your partner."
Did Mendel choose to complicate his work for a reason? What there data that the more simple explanation did not address?Students will not know what it means to "study a second trait." You need to provide a question or challenging example and then have them discuss in pairs possible answers. What justification, in addition to their "guess," will you want them to share out?
I will open this up for discussion and students will talk to their partner at their table to generate ideas about how they could manipulate a punnett square to accommodate another trait being studied. After discussing what some of the groups come up with (possibly one group coming up with a correct answer) I will show them how Mendel introduced this second trait. NIce! I like the idea of allowing students to try to answer question before you share Mendel's approach.
"If you guys look in your books at page 261 you will see the same thing you saw in Monohybrid crosses, a punnett square. However, obviously its a little different. Can anyone tell me why this punnett square is different?"
"You guys." Really? Are you a teacher or a classmate? An easy thing you can do to elicit respect is to act/speak like an adult. It's your choice, but this is a simple step. The young women in your classes could take offense.
- Size (# of squares)
- 2 traits instead of 1
- Different RATIO
Do students learn why these ratios appear, or is this a rote rule? Can you explain it to them?Hopefully students will name all 3 of these, if not I am assuming that the one they will not get is the difference in ratios between the monohybrid and dihybrid cross. Obviously I will not just give them the answer, but will help guide them to it.
- Activity 2: Dihybrid Cross worksheet
After having students read a little bit about Dihybrid crosses I will hand them a worksheet which will engage them further. What will you have them read? Do you remember reading in class? Why didn't you assign this the previous night?- Master 16 Dihybrid Worksheet
Students will work on this worksheet independently and then after a little while we will come together as a class and go over it.Can you think of a way not to go over the worksheet? This is usually a waste of time, since no one pays attention. (Why should they?)
Now that students have the concept of Mendel and all of his work, I am going to introduce my project for this section which is titled MendALIEN genetics. This is a project that is due on the same day as the Chapter Test (Day 5) and gives students the chance to create their own alien by using punnett squares (see rubric, procedure, questions for more details). ------ This has not yet been created, I am working on it.Activity 3: MendALIEN Genetics
- Rubric
-
Mendalien Genetics Procedure.pdf
- Details
- Download
- 214 KB
- Questions
Reading these aloud with the class will guarantee that students understand what is expected of them and how I will be grading them on this assignment as well. Any questions can be answered and students will have the opportunity to begin working on this project if they want (although I don't expect their to be much class time left by the end of the period).What will you do to generate enthusiasm for the project?
Closure:
How about asking a summary question for the day and having students volunteer answers?
Assessment:
Reflections
(only done after lesson is enacted)Student Work Sample 1 – Approaching Proficiency:
Student Work Sample 2 – Proficient:
Student Work Sample 3 – Exceeds Proficiency: